Punching in R.C. Slabs

Abstract

An experimental test program has provided the basis for the mechanical model presented here to estimate the punching resistance of axisymmetric reinforced concrete slabs subjected to concentrated loads or reactions. The proposed model has the advantages of describing the slab behavior beyond the cracking stage and of estimating both punching and flexural capacities of such slabs. Material characteristics are defined by generally accepted stress‐strain relationships for uniform stress states and a formulation dependent on the stress gradient for the stress concentration region near the column or load. Failure criteria are expressed in terms of limiting strains or the limit at which tension is developed in the critical region of concrete. The dependence of the theoretical punching resistance on the influential parameters is illustrated and compared with the predictions of codes of practice. Finally, calculated and experimental punching strengths are compared and shown to correlate very well for a wide range of test slabs.